Android Checkbox - Background + Button Layout - wrong size

I think I don't see an error in one of my layouts. I want to show a checkbox and a border around it.

I have generated images using Android Holo Colors Generator

I tried to add a shape to the checkbox, which worked fine on Nexus 4, but didn't display the button at all on any other device, so I added a dummy layout:

Markup:

<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginRight="5sp"
    android:layout_marginTop="3sp"
    android:background="@drawable/shape_button" >

    <CheckBox
        android:id="@+id/check"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:button="@drawable/btn_radio_holo_dark_hm" />
</LinearLayout>

      

        
        
        
      

    

the form:

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">

    <solid android:color="@android:color/transparent"/>

    <stroke
        android:width="1px"
        android:color="@color/gray" />

    <corners
        android:bottomLeftRadius="5sp"
        android:bottomRightRadius="5sp"
        android:topLeftRadius="5sp"
        android:topRightRadius="5sp" />

</shape>

      

        
        
        
      

    

I now get the following:

I tried setting minWidth depending on mdpi / hdpi / xhdpi, but the button never appears centered on every device. fill_parent / wrap_content doesn't make any changes, also moving the button inside the layout.

Any suggestions on what is wrong here?